F body headers in an A-body?

I think you're in luck. Summit lists the same part number for their headers on a V8 Duster as they do a V8 Volare. You got me curious, I had to check for myself. But because they advertise the same part number you might want to consider this a "one size fits most" application. The K-frame on the F-bods is huge compared to the A-bod, so it might take some trial and error and some good use of vocabulary. But the price just might make it worth the effort for your budget.